Radio coexistence systems have been developed in which there are two or more user categories enabling prioritization of users for radio channel usage. A first user, which may be referred to as a primary user, may have priority over a second user, which may be referred to as a secondary user, for using a certain radio channel and bandwidth. For example, the primary user may be a licensed user and the secondary user a non-licensed user of the bandwidth. There may be primary users and secondary users also within a group of licensed (or non-licensed) users of a bandwidth. For example, a user first communicating on a radio channel may be a primary user and have priority over later-starting secondary users on that channel. There generally exists a need to arrange use of radio bandwidth for primary users and secondary users as efficiently as possible.